Aqueous Co(II) adsorption using 8-hydroxyquinoline anchored γ-Fe2O3@chitosan with Co(II) as imprinted ions

• γ-Fe2O3 has been synthesized through solvent free route using solid reagents.
• 8-Hydroxyquinoline anchored chitosan biopolymer has been synthesized.
• Magnetic ion imprinted modified chitosan was synthesized for cobalt adsorption.
• The sorbent showed good efficiency for cobalt adsorption.

A novel, bio-based 8-hydroxyquinoline (8-HQ) anchored magnetic chitosan using Co(II) as imprinted ions was prepared and applied for selective removal of Co(II) from aqueous solutions. At first, γ-Fe2O3 has been synthesized by solvent free precipitation route and then combined with 8-hydroxyquinoline anchored chitosan using epichlorohydrin (EPH) as crosslinking agent. The FT- IR spectra showed that 8-HQ has been successfully anchored onto chitosan structure. Moreover, TEM analysis confirmed that the nanocomposite has core–shell structure. The experimental results showed that equilibrium time was 10 min moreover, the maximum adsorption capacity of Co(II) with non-imprinted and surface imprinted polymer at pH 8 were 66.6 and 100 mg g−1, respectively. The selectivity coefficient of Co(II) ions relative to Cd(II), Ni(II) and Pb(II) were 11, 42 and 2, respectively. Prepared biosorbent represented good stability and good repeatability after three cycle of sorption and desorption using 0.5 mol L-1 of HNO3 as eluent. Kinetic and thermodynamic behavior were also investigated and result showed that cobalt adsorption followed second order model and endothermic path.